This proposal is directeed to the investigation of the toxicology of environmental chemicals. Research will be undertaken on an interdisciplinary basis under the following objectives: 1) To determine the biochemical reactions and interactions of exogenous chemicals in producing effects in biological systems. 2) Investigate the direct and combined effect of environmental chemicals on the production and course of neoplasia in animals. 3) To determine the physical chemical properties and chemodynamic data of chemicals and develop new and more sensitive analytical methods for potentially hazardous contaminants. The work involves 12 investigators and a number of disciplines. They intend to pursue studies on molecular and biochemical mechanisms whereby xenobiotics effect levels of gluthathion and related thiols induction of porphyria and membrane function and structure. The role of chemicals in the production and course neoplasia in animals will be followed. New and more sensitive methods of analyses for certain contaminants and potentially hazardous chemicals will be developed. In addition, photochemistry of many of these chemicals will be determined.